CVE-2026-101019
NGINX ngx_http_js_module vulnerability
NGINX JavaScript (njs) has a vulnerability where the njs XML module exposes entity-backed XML attributes inconsistently with libxml2 canonicalization. In both the built-in njs and QuickJS backends during the canonicalization process, the $attr$Name getter may return undefined for an explicitly present attribute containing an internal entity reference. The $attrs getter may return a value derived only from the first attribute child. This may allow an unauthenticated attacker that invests significant effort in obtaining a genuinely signed document to skip validation while signature verification succeeds. An nginx-saml deployment is a confirmed affected consumer when run with the built-in njs backend.
Impact
In affected signed-XML consumers, an unauthenticated attacker can cause security-relevant attributes to appear absent or truncated while signature verification succeeds. In nginx-saml, this can bypass expiry, Destination, and request-correlation checks, enabling replay or acceptance of a response outside its intended context. It does not permit signature or identity forgery, or a direct availability impact. There is no control plane exposure; this is a data plane issue only.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Affected Products
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CVE record
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NVD configurations
No data
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Red Hat packages
No data
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OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| F5 | NGINX JavaScript | unknown |
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| Vendor | Product | Versions | ||||||||
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| F5 | Nginx Javascript |
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Remediation
Vendor Workaround
Applications processing signed XML should reject DTD-bearing input before calling xml.parse(). The check must cover the complete document after decoding its accepted input encoding; a parser-level DTD prohibition is preferable to a raw byte search for "<!DOCTYPE". Applications should also treat absent security-relevant attributes as validation failures rather than optional values. nginx-saml deployments should explicitly validate Destination, request correlation when unsolicited SSO is not intended, assertion validity, bearer SubjectConfirmation, Recipient, and SubjectConfirmationData InResponseTo.
Tracking
Advisories
Metrics
Attack Vector Network
Attack Complexity Low
Privileges Required None
Attack Requirements Present
User Interaction None
Vulnerable System Confidentiality Impact High
Vulnerable System Integrity Impact Low
Vulnerable System Availability Impact None
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
Attack Vector Network
Attack Complexity High
Privileges Required None
Scope Unchanged
Confidentiality Impact High
Integrity Impact Low
Availability Impact None
User Interaction None
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.210% probability within 30 days)
Exploitation none
Automatable no
Technical Impact partial
| Link | Providers |
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| https://my.f5.com/manage/s/article/K000162615 |
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| Type | Values Removed | Values Added |
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| First Time appeared |
F5
F5 nginx Javascript |
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| Vendors & Products |
F5
F5 nginx Javascript |
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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| Type | Values Removed | Values Added |
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| Description | Description NGINX JavaScript (njs) has a vulnerability where the njs XML module exposes entity-backed XML attributes inconsistently with libxml2 canonicalization. In both the built-in njs and QuickJS backends during the canonicalization process, the $attr$Name getter may return undefined for an explicitly present attribute containing an internal entity reference. The $attrs getter may return a value derived only from the first attribute child. This may allow an unauthenticated attacker that invests significant effort in obtaining a genuinely signed document to skip validation while signature verification succeeds. An nginx-saml deployment is a confirmed affected consumer when run with the built-in njs backend. Impact In affected signed-XML consumers, an unauthenticated attacker can cause security-relevant attributes to appear absent or truncated while signature verification succeeds. In nginx-saml, this can bypass expiry, Destination, and request-correlation checks, enabling replay or acceptance of a response outside its intended context. It does not permit signature or identity forgery, or a direct availability impact. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated. | |
| Title | NGINX ngx_http_js_module vulnerability | |
| Weaknesses | CWE-436 | |
| References |
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| Metrics |
cvssV3_1
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